The length, breadth and height of cuboid are in the ratio 3 : 2 : 1 and its volume is 162 cm³; the longest side of the cuboid is:

1. 6 cm

2. 9 cm

3. 18 cm

4. 54 cm

The length of a cuboid is doubled, breadth is halved and height is tripled, the volume of the cuboid will become :

1. 1.5 times

2. 2 times

3. three times

4. six times

Each side of a cube is tripled, its surface area will become :

1. 3 times

2. six times

3. nine times

4. 27 times

A cuboid has a total surface area of 80 m² and the lateral surface area of 50 m²; the area of its base is :

1. 30 m²

2. 60 m²

3. 15 m²

4. 10 m²